Improved vacuum-pan for condensing milk and other substances



G. R. PERCY.

v Vacuum Fan for Condensing Milk, &c. Nb. 52,197. Patented Jany 23,1866.

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- to bring about evaporation.

, a vacuum inside the pan.

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GEORGE R. PERCY, OF NEW YORK, N. Y.

IMPROVED VACUUM-PAN FOR CONDENSING MILK AND OTHER SUBSTANCES.

To all whom it may concern:

Be it known that I, GEORGE R. PERCY, of the city, county, and State ofNew York, have invented a new and useful Improved Mode of ConstructingVacuum Condensing-Pans and I do hereby declare the following to be afull and exact description of the same, reference being had to theaccompanying drawing, and to the letters of reference marked thereon.

Before giving a description of my invention I will describe a vacuumcondensing-pan of the ordinary mode of construction.

The common vacuum-pan is generally built of copper, and is in shape verymuch like a hens egg, that being a form well adapted for giving strengthto resist the pressure of the atmosphere and for giving space inside forthe evaporation and condensation of fluid substances. A pipe ofconsiderable size-about eight inches fora pan five feet in itslongitudinal diameter-connects with this pan in the middle of its uppersurface, and connects indirectly with an air-pump. This pipe is forexhausting the air from the vacuum-pan, and also for drawing off thevapor given up by evaporation inside the pan. The pipe, however, firstconnects with a condenser and the condenser with the pump. The condenseris generally a vessel in which water falls in jets or spurts, and isused for condensing the vapor before it goes to the pump. The lower partof the vacuum-pan is built with a jacket, or, as I may call it, a doublebottom. Steam is admitted inside of this jacket or double bottom for thepurpose of heating the substance which may be inside of the pan. Besidethe jacket or double bottom for heating, there is usually a pipe coiledtwo or three times around the interior surface of the pan down wellunder the fluid and near the jacket. This pipe is heated with steam andaids the jacket In the process of evaporation the air-pump is started toform The substance to be evaporated is then drawn into the pan and thesteam let into the jacket and the coil. As soon as the fluid issufficiently heated it will begin to evaporate. Most of the vacuum-pansnow in use are made as I have described. For

the past twenty years there have been few improvements made in theconstruction of the vacuum-pans.

By the plan I propose the principle of heating and evaporating liquidsin vacuo will be very different. I will first give a description of myimproved mode of constructing vacuum condensing-pans and then show howthey differ from those in common use and wherein they are better.

To enable others skilled in the art to make and use my improved vacuumcondensingpans, I will proceed to describe its construction andoperation, reference being had to the accompanying drawing, and to theletters of reference marked thereon.

The exterior or shell of my improved vacuum-pan is made as they now makethem, except that no jacket or double bottom is needed. This shell maybe made of any shape to resist the pressure of the air. The best shape,however, has been found to be oval.

A in the accompanying drawing represents the shell of the vacuumcondensing-pan.

a represents a simple ring of pipe, perforated with holes upon its undersurface, and is used for feeding the substance to be condensed into thevacuum-pan. In the accompanying drawing this feeder a has a piece ofmetal with a serrated edge fastened to the middle of its under surface.This is for the purpose of more evenly distributing the fluid upon thepipe below. This piece of serrated metal is lettered b. When it isattached to the feeder, as represented in the accompanying drawing, theholes in the feeder are just at the sides of the metal.

0 is a pipe, which connects with a reservoir and supplies the feeder bwith the fluid to be condensed. cl is a stop-cock in the pipe 0.

The feeder, instead of being a pipe with perforated holes on its undersurface, may be constructed in the form of a trough with a continuousopening for the discharge of fluid substances, or it may have slits orholes, or both. Instead of a trough a box with open ings on its undersurface may be used. The object is to have the substance flow in'thinsheets or fall in drops upon the heated pipes or surface below. Directlyunderneath the feeder a is aseries of pipes, (represented byf.) Thisseries of pipes lettered f should be directly underneath the feeder, andmay be of more or less number to suit the builder. They should be largeenough to admit hot liquids a turn.

or steam to course through them, pipes of about two inches in diameterbeing the best size, as they can be readily heated and present a goodsurface for evaporation. There should be about four to every uprightfoot, and four or five feet is the best height. The pipesf also havepieces of metal with a serrated edge upon their under surface, and arelettered m. These may be discarded in many instances, and at no time arethey indispensable. The pipesfare connected together by short pipes,(lettered g) to allow the steam or heated fluid to pass from one pipe toanother through the series.

h represents a pipe for supplying the pipes lettered f with steam orheated fluid. j is a stop-cock in the pipe h. 7c is a pipe connectingwith the lowest of the series of rings or pipes f, and is adischarge-pipe for steam or heated fluids.

In a large vacuum-pan it may be necessary to have the series of pipes ffed by more than one supply-pipe, and consequently have more than onedischarge-pipe. Every three or four rings may have a supply and adischarge pipe.

My process for condensation is this: I first make a vacuum in my vacuumcondensingpan by setting the air-pump to work. I then turn on steam orheated fluids (the heated fluid, such as hot water, may in manyinstances answer a better purpose than steam) into the pipes f throughthe pipe h, and leave it to course through the pipes f andconnecting-pipes g, and discharge itself through pipe k, until the pipesf are sufficiently heated to cause evaporation to the fluid passing overtheir surface. I keep them up at the proper point for evaporation bycontinuing to let the steam or heated fluid pass through them. When thepipes are sufficiently heated to cause evaporation I turn the fluidwhich is to be condensed into the feeder (a through the pipe 0. Thefluid fills the feeder, and then runs or trickles from it and falls uponthe heated pipe below, and, running over this pipe, falls upon the nextone below, and so on over the whole series of pipes represented by f,and falls from the last one into the bottom of the vacuumpan or anyvessel placed therein for its reception. There might be a vessel uponthe bottom of the vacuum-pan to receive the condensed product, but it isnot necessary. The operator, by examining the fluid which has thusdropped into the bottom of the pan by means of a test-stick,can at onceregulate the degree of condensation. If he Wishes the substance to bemore condensed, he should let the fluid more slowly into the feeder andheat his evaporating surface to a higher degree. Of course the morefluid there is trickling over the heated pipes the less it will becondensed.

The test-stick mentioned above is in quite common use, and is a shorttube running through the shell of the vacuum-pan. When it is withdrawnthe hole is closed by giving it The tube brings with it some of thematerial inside the pan. After the fluid has been condensed to therequired consistence, or any time that the vacuumpan gets too full, thecondensed substance is discharged from the bottom of the vacuum-pan intoany receptacle placed below. This may be done without breaking thevacuum in the pan by a mode very simple in its operation.

The vessel below may be attached to the vacuum-pan by a pipe. The airmay be exhausted from the vessel below, and the discharged substancefrom the vacuum-pan will then fall into a vacuo.

The plan that I have adopted above for constructing my improvedvacuum-pan is by no means the only one that can be used. The pipes,instead of being constructed in coils, may be made straight and run inparallels back and forward in the pan, or they may run transversely, orbe fashioned into any device to suit the builder. Instead of pipes acorrugated surface of metal may be used; or the pipes, instead of havinga piece of metal with serrated edge upon the lower surface, may have aplain metal attachment, or they may be placed near enough together sothat no metal will be needed. The pipes might be placed close together,so that they would touch. The series of pipes might be formed in theshape of acornucopia,the substance to'be condensed running or tricklingover the surface. Smooth, roughened, or corrugated metal might also bemade in the shape of a cornucopia. The pipes or the smooth, roughened,or corrugated metal might be inclined. at an angle for the fluid to runover them, or the fluid might be made to run along the pipes by somedevice, or along the roughened or corrugated metal.

I do not claim as new any particular mode of constructing myfeeding-pipe for introducing the fluid to be condensed into the pan. Nordo I claim as new any device or mode of constructing pipes for heating,or of any metal surface for the substance to run or trickle over whilecondensing. The plan which I have made in my drawing hereto annexed ofpipes and feeder is from one in common use among brewers for cooling aleand malt liquors. I do not claim as new any particular form ofconstructing the exterior surface or shell of my vacuum-pan.

I do not claim in my application the mode of heating the vacuum-pan byradiating heat, as adopted by J. J. Miller in Letters Patent issuedDecember 23, 1862, and November 17, 1863. By his process substances tobe condensed run over heated surfaces heated by radiation, or are causedto evaporate or condense by heat aronnd the interior surface of thevacuum-pan. It thus forms a chamber and this chamber is heated byradiated heat.

By my process the substance to be condensed or evaporated runs ortrickles over a surface of pipes or metals heated by hot air, steam, orhot fluids passing within the pipes over which the fluid trickles orruns,.or apsubstance.

plied next to the surface of the metal over which the substance to becondensed or evaporated trickles or runs within a vacu um.

I will now mention some of the advantages that my method of evaporatingand condensing in vacuo possesses over the method in common use.

First, with the vacuum-pan now in use the whole body of the fluid withinthe pan has to be heated up to the boiling-point of fluids in monobefore it commences to evaporate or condense, and to evaporate fast ithas to be kept above that point of heat. It thus requires a higherdegree of heat to the substance to be evaporated or condensed than thepoint at which it will evaporate or condense. Moreover, this degree mustbe kept up during the entire operation. The fluid is thus kept in astate of continued commotion and violent ebullition, which in many casesis highly injurious to the Portions already condensed are in danger fromthe continued heat of being burned or deprived of their essentialproperties. By my process only those portions of the fluid are heatedwhich are actually undergoing evaporation or condensation, and onaccount of the separation of the particles but a very little greaterdegree of heat is required than the degree at which evaporation orcondensation actually takes place. Moreover, there is no violentcommotion of particles, and condensed portions are received in thebottom of the pan, where no further heat is applied to them. I thusobviate by my process, (a) an unnecessary degree of heat; (1)) commotionand breakage of particles; (0) injurious heating of portions alreadycondensed.

Second advantage: The far greater area of evaporating and condensingsurface afforded by my improvement. In the old pan the evaporating orcondensing surface is limited by the superficial surface of thesubstance undergoing evaporation or condensation. In my pan it is onlylimited by the superficies of the pipes or other appliances over whichthe substance to be evaporated or condensed is caused to percolate ortrickle. For instance, the series of pipes, as represented in mydrawing, would afiord a superficial surface of about eighty square feet,the pipes in that case being about two inches in diameter, the coils orrings three feet in diameter, and the height of the pipes about fourfeet, or over. In the old pan the superficial surface of one four feetin diameter would only be twelve square feet. A pan constructedaccording to my method of the same size would give about six times theamount of evaporating and condensing surface.

Third advantage: By the old plan only steam can be used for heatingpurposes, while with my plan hot water or other heated fluids may beused. Steam will often cause things to burn while condensing, but withhot water there is no danger of burning.

Fourth advantage: My process very materially difiers from the old planin this, that, instead of heating a body of fluid up to anevaporating-point with the heat applied to its bottom or sides, thesubstance runs or trickles over the heating surface.

Fifth advantage: That my method may be introduced into most of the pansnow in use, if desired. The feeder, coils, pipes, corrugations, orheated surface may be introduced into most of the pans now used withoutmuch expense.

Having thus described the manner of constructing and using my improvedvacuum condensing-pan, I claim as new and desire to secure by LettersPatent 1. The combination of the shell A with the series of pipes f f,the feeder a, the connecting tubes 9, substantially as described, invacuo.

2. The combination of the feeder a with the shell A, whether with orwithout the pipes ff,

when used in 0660260.

3. The combination of the ordinary vacuum condensin g-pan with thepercolating, trickling, and heating apparatus, as above described.

4. The introduction into a vacuum-pan of liquids in drops, smallparticles, or thin sheets, when for the purpose of evaporation orcondensation in cacao, and when used in combination with a directheating-surface, and not one formed by radiation, and the liquor to becondensed or evaporated running or trickling over such heated surface.

5. The method or mode, as above described, of evaporating and condensingin vacuum at low temperatures.

6. The percolating, separating, disruption, and disintegration ofsubstances in mono, as above described.

7. The production and application of a uniform rate of temperature inand to substances while undergoing evaporation and condensation in vacuoby means of their running or trickling over a surface of pipes or metalsheated by the direct application of steam, hot air, or hot fluids tosaid pipes or metals, as above described.

In testimony whereof I have hereunto subscribed my name.

GEORGE It. PERCY. Witnesses:

GEO. T. HOUGH, SAML. A. PERCY.

